Six were arrested as a result of their interaction with the decoy officers in Main South and charged with sexual conduct for a fee: Danielle Hamalainen, 29, of 101 Endicott St.; Jamie Francis, 34, of 24 Pocasset Ave.; Kerri Sheehan, 39, of 122 Barnard Road; Yuhong Jiao, 46, of 30 Orchard Park Drive, Reading; Crystal Polydores, 32, of 17 May St.; and Margarita Aponte, 29, of 54 Gifford Drive.

Police said vice officers working the prostitution sting saw a silver Ford Taurus in traffic and recognized the driver as Javier Crespo, 27, of 191 St. Nicholas Ave. The officers, working under cover, followed the car because they knew of Mr. Crespo because of previous drug investigations, police said.

The officers said they saw the Taurus enter the parking lot of 7 Laurel St. They saw a woman, whom they identified as Roselia Delrosario, leave the Laurel Street apartment and enter the rear seat of Crespo’s vehicle. The Taurus drove out of the parking lot, traveled a short distance and stopped to pick up a man on Gage Street. The vehicle drove on for a short distance and dropped off the male passenger, police said. The officers said they then saw Mr. Crespo get out of the car, place a box in the trunk; get back into the vehicle and drive off.

Police said the officers stopped the car on Laurel Street and discovered heroin weighing about 180 grams in the box in the trunk.

Mr. Crespo was charged with trafficking in heroin and conspiracy to violate controlled substance laws. One passenger, Megan Fridley, 25, of 191 St. Nicholas Ave., was charged with conspiracy to violate controlled substance laws. The other passenger, Ms. Delrosario, 34, of 7 Laurel St., was charged with trafficking in heroin and conspiracy to violate controlled substance laws.